Process and apparatus for drying packages of artificial silk



1941 E. MENGERINGH AUSEN ETAL 2,266,375

PROCESS AND APPARATUS FUR DRYING PACKAGES OF ARTIFICIAL SILK Filed Feb.5, .1938

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lilwizllezgem'nyfiwlm Patented Dec. 16, 1941 PROCESS AND APPARATUS FORDRYING PACKAGES F ARTIFICIAL SILK Ernst Mengeringhausen, Oberbruch,Bezirk Aachen, Germany, and Ludwig Silberberg, Arnhem, Netherlands,assignors to American Enka Corporation, Enka, N. 0., a corporation ofDelaware Application February 5, 1938, Serial No. 189,000

Germany August 31, 1933 Claims. (01.34-)

Several different methods exist for drying un-- supported packages ofartificial silk in which various systems are employed to effect a dryingsubstantially from the inside to the'outside of the package. tages maybe realized when conducting the drying in such a manner; one of the mostimportant is that unequal shrinkage from the inside to the outside ofthe package is substantially overcome. Prior to the advent into theindustry of the so-called inside outside drying, packages of artificialsilk had to be either wound into skeins in order that a uniformshrinkage could be had, or the packages were placed in large oven driersand the drying took place substantially from all directions throughoutthe body of the package. The former method-offered the disadvantage ofnecessitating an extra. expensive operation with the resultant increasein the amount of handling of the filaments thereby weakening, tanglingor breaking the same. The latter method produced unequal shrinkagethroughout the package owing to the fact that the outer layers of yarncould not shrink to the .same ektent as the inner layers because of thethrough the same and the drying would take place substantially from theinside progressively to the outside of the package. Such a process wasIt is known that stveral advantherefore more uniform contraction, it wasapparent that the so-called inside-outside drying method was animprovement over the old practice of rewinding, into skeins and dryingthe same. In other words, although the current methods for carrying outthis inside-outside drying produced small shrinkage difierences in thethread, the trend in the industry was to adopt this simplified process,provided a practical system could be worked out.

Thisinvention, therefore, has for an object the provision of a methodfor improving and facilitating the inside-outside drying of artificialsilk packages.

It is further contemplated to conduct the drying operation in vacuo sothat the drying operation can be efiected at very much lowertemperatures' than would otherwise be possible.

Another object of the invention is the provision of an improvedapparatus for carrying out the present process. ,v

Other objects and advantages will be apparent from the followingdetailed description and when considered in connection withtheaccompanying drawing wherein:

Figure 1 represents a longitudinal section of a vacuum drier formed inaccordance with the invention which is particularly constructed topermit the practice of this process, packages of artificial silk beingshown in proper position for dry n Figure II is a transverse sectiontaken on lines 2-2 of Figure I;

Figure III illustrates in detail one of the loading tubes with severalfreshly spun and washed artificial silk packages thereon in readiness tobe slipped over a heating cylinder within the drying chamber.

'40 Referring to the drawings, the numeral l in- .rlicates a metalliccontainer suitably lined with "an insulating material 2 such as corkwhich very found to be comparatively successful due to the fact that theinner layers of thread tended to dry first and thereby leave space forthe outer layers to contract. One of the objections to this method wasthat the higher drying temperatures still caused inequalities in thefinished thread. Howefiectiviely prevents any temperature changes withinthe container from external causes. The container is provided withanumber of heating cylinders 3, the open ends of which are integrallyfixed to a plate 4 and the closed ends have insulating caps attachedthereto. The plate 4 is spaced a short distance from the closed end ofthe container and forms a header chamber 5 therewith. This chamberserves as a space for introducing and exhausting the heating medium,namely through pipes 6 and I, respectively. The heating medium such ashot water, steam or oil is passed through inlet pipe 6 is forced intothe heating cylinder 3 by way of smaller pipes a located within the saidcylinders.

With reference to Figure III, the artificial silk packages 9 arearranged side by side in contact on a loading tube Ill. The diameter oftube l is sufficiently less than that of the packages to permit completecontraction on drying. Each of the loading tubes is adapted to beslidably mounted on one of the heating cylinders 3 (Figure I) in such amanner that the open end of the loading tube is in contact with analuminum plate I I. In order to prevent the introduction of any heat byconduction into the drying chamber proper designated at I 2, exceptthrough the heating tubes,

several insulating elements are employed in addition to the lining 2. Inthis connection between and I l by conduction. To prevent this, coldwater is circulated through a shell l3 surrounding plate 4. A pipesystem (not shown) for circulating cold water is welded to the hack ofthe aluminum plate I I. A layer of magnesia I4 is preferablysuperimposedover the insulation behind the aluminum plate to further prevent theheating of the plate. Such precautionary measures confine the heatingmedium entirely to the heating cylinders whereby drying takes placeexclusively from the inside of each package to the outside. In order toavoid improper dryingof those ends of the packages on the extremities ofthe respective heating cylinders that would normally be exposed, asuitable material such as portions of artificial silk packages orasbestos pads l5 may be utilized as insulating coverings therefor.

At its front end the container is provided with a hinged cover member l6which is lined with an insulating material so that when the cover isclosed and secured by lock nut-s II, a hermetically sealed,temperatureand pressure-proof chamber is formed. Air and moisture areevacuated from the chamber by means of pipeline l8 connected to a vacuumpump (not shown).

Various modifications and changes canbe made in the details of theaforedescri-bed apparatus withoutdeparting from the spirit and scope ofmy invention. However, the general arrangement offers a distinctimprovement over the prior practice. In proceeding inv accordance withthe present invention a plurality of rayon packages are preferablyplaced upon loading tubes and the tubes are mounted on heatingcylinders. The cover member is then closed and tightly secured by meansof lock nuts I! and air from the chamber is evacuated to the greatestdegree possible with commercially feasiblemechanism. In practice avacuum of from 5 to 15 mm. of mercury (absolute pressure) is attainedduring the initial drying period. At this pressure the moisture boilsoff at approximate temperatures from 4 C. to 20 C. As the moisture boilsoff. it absorbs the heat from the heating tube and thereby acts toprevent the temperature from rising in the chamber.

The water or other heating medium circulating through the heatingcylinders is maintained at a temperature of about 70 C. Due to theaforedescribed construction of the apparatus, the only heat that canenter the drying chamber in appreciable quantity is transmitted by wayof the heating cylinders per se. As this heat first contacts the innerportions of the packages, the drying proceeds exclusively from theinsides to the outsides thereof. The extremely high vacuum permits thedrying totake place at a much lower temperature than would otherwise bepossible. Moreover, the drying in vacuo greatly improves the process andimparts extremely uniform qualities to the finished thread.

What we claim is:

1. A method of drying tubular wound packages of freshly spun artificialsilk which have threadfree centers, which comprises positioning aplurality of such artificial silk packages in a drying chamber,evacuating the drying chamber sufficiently to maintain a high vacuumabout the outer surfaces of the packages and applying heat solely by aconfined heating medium circulated within the thread-free centers of thepackages without directly contacting the inner threads with the heatingmedium to effect progressive drying and resultant progressivecontraction of the thread in each package from the interior toward theexterior thereof.

2. A method of drying tubular wound v packages of freshly spunartificial silk which have thread-free centers, which comprisespositioning a plurality of such artificial silk packages in a dryingchamber, evacuating the chamber suf-' ficiently to subject the packagesto a vacuum of from 5 to 15 mm. of mercury (absolute pressure), at whichpressure the moisture boils oil at a temperatureof about4 C. to 20 C.,applying heat to the packages solely by a confined heating mediumcirculated within the thread-free centers thereof 'while protecting theends of the packages sufficiently to substantially prevent theirpremature drying to thereby effect progressive drying and resultantprogressive contraction of the thread in each package from the interiortoward the exterior thereof, continuously withdrawing the vapor formedin the chamber due to the drying of the packages, continuously supplyingthe heating medium to the cores of the packages and withdrawing ittherefrom without directly contacting the inner threads of the packageswith the heating medium.

3. A process for drying tubular rayon packages which comprisesassembling a plurality of freshly spun wound packages on an imperforateloading tube, positioning the tube within a drying chamber, maintaininga vacuum about the outer surfaces of the packages and heating thepackages solely by supplying a heating medium within said imperforateloading tube'whereby the drying of each package is effectedprogressively from the inside to the outside.

4. A process for drying tubular rayon packages which comprisesassembling a plurality of freshly spun wound tubular packages on animperforate loading tube, positioning the tube within a drying chamber,maintaining a vacuum about the outer surfaces of the packages andheating the packages solely by a heating medium within said imperforateloading tube and withdrawing the same therefrom without directlycontacting the inner threads of the packages while maintaining a highvacuum thereon such that a boil-01f of the -moisture is effected at atemperature below 20 C. whereby drying of the packages takes placeprogressively from the inside to the outside.

5. A method of drying tubular wound packages of freshly spun artificialsilk which comprises the steps of forming thread-free drying passages byarranging a plurality of such packages with their adjacent ends abutted,applying heat solely by a confined heating medium within the said pas.

adjacent ends abutted, maintaining the packages with their endsprotected to prevent premature drying, heating the ackages solely bysupplying a confined heating medium to the said passages withoutcontacting the inner threads of the packages to effect drying of thepackages from the inside to the outside, and during the drying periodmaintaining a vacuum on the outer surfaces of the packages of from 5 tomm. of mercury (absolute pressure), at which pressure the moistureboilsofl at a temperature of about 4 C. to C. I

7. An apparatus for drying rayon packages which comprises a containercapable of being hermetically sealed to form an air-tight dryingchamber, imperforate tubular members, each supported at one end forreceiving thereover a plurality of tubular rayon packages in each of aplurality of rows within said container with the packages in each rowhaving their thread-free centers in alignment, means for supplying aheating medium solely within the imperforate tubular members andwithdrawing the same therefrom without contacting the inner threadsofthe package. said means being so positioned with respect to the saidmembers that the heat supplied within the same, is transmitted initiallyonly to the inner surfaces of the packages thereby avoiding the packagesmay be dried at a very low temperature spective tubular projections,each of the loading tubes being formed to be passed through thethread-free centers of a plurality of tubular rayon packages with theirends abutted, means constituting substantially the sole heating sourcefor the area within the chamber arranged in each of the tubularprojections for directing a circulation of a heating fluid therethroughthereby to effect the application of heat to the interior of eachpackage suspended upon a loading tube engaged thereover whileavoiding'the subjection of the outer portion 'of each package to thedirect application of heat, means for evacuating the drying chamber topermit the respective packages to be dried at a very low temperatureprogressively from the inside to the outside thereof,

whereby a plurality of rayon packages maybe suspended upon each of theloading tubes and placed in the drying position within the containerupon the engagement of the loading tubes with the respective tubularprojections and thedrying may be effected by sealing the closure,evacuating the chamber and circulating the heating fluid within theprojections.

9. A method of drying tubular wound packages of freshly spun artificialsilk which have threadfree centers, which comprises positioning aplurality of such artificial silk packages in a drying chamber,evacuating the chamber sufiiciently to maintain a high vacuum on thepackages, heating the packages solely through the medium of imperforateheat emitting means confined within the thread-free centers thereof, thedrying of the packages being effected substantially entirely solely bythe passage of heat from the heat emit- .ting meansand the action of thevacuum, whereby drying .and the resultant contraction of the thread ineach package is progressive fro the interior toward the exterior.

10. A method of drying tubular wound packages of freshly spun artificialsilk'which have threadsubjection of the outer portion of the packages.

to the direct applicationof heat, and means for evacuating the dryingchamber whereby the progressively from the inside tothe outside of eachthereof.

8. An apparatus for drying rayon packages which comprises a containerhaving a closure ca-' ,pable of being hermetically sealed to form anairtight drying chamber, imperforate tubular pro jections extending intothe container from one wall thereof, said tubular projections beingclosed free centers, which comprises positioning a plurality of suchartificial silk packages in a drying chamber, evacuating the chambersufiiciently to maintain a high vacuum on the packages, heating thpackages solely through the medium of imperforate heat emitting meansconfined within the thread-free centers of the packages, the heating ofthe packages being effected solely by the passage of radiant heat andheat of conduction from the heat emitting means, whereby drying and theresultant contraction of the thread in each package is progressive fromthe interior toward the exterior.

ERNST MENGERINGHAUSEN. LUDWIG SILBERBERG.

